One form of on-belt analyser, which utilises a thermal neutron capture and gamma ray production technique known as PGNAA (Prompt Gamma Neutron Activation Analysis), is employed to analyse the composition of material such as coal or other mineral product transported on a conveyor belt. The analyser has a C-shaped housing provided with lifting points to allow the analyser to be appropriately positioned across a path of the belt. The weight of the analyser is quite substantial, in the order of 6500 to 9000 kg and the lifting points are necessarily provided at a base of the analyser due to structural load-bearing limitations of the housing. Once positioned, removable side shielding is fitted to close the open side of the C-shaped housing, to thereby define a tunnel in the order of 2 meters long, through which the belt passes.
The tunnel has a radiation source in its base and sensors in the roof thereof. Tunnel slider panels are provided above the radiation source to support the belt as it passes through the analyser.
Installation and operating costs of the analyser are relatively high given the analyser generally needs to be installed in a shed or the like for protection from the elements and various component parts such as the slider panels are subject to wear during operation. Also, in order to install the analyser substantial parts of the conveyor belt support structure, such as frame work and stringer or idler wheels, need to be removed. The remaining structure, at either side of the analyser, then needs to be configured in order to ensure an appropriate profile is applied to the conveyor belt, as it enters the analyser, compatible with the shape of the tunnel and the slider panels.